Such pressure valves are known in the art. An example of which is shown in FIG. 1. This type of pressure relief valve is used in hydraulic or pneumatic systems, e.g., to limit the pressure in specific branches or lines of the respective circuits. In order to do so, the pressure relief valve has a housing in which a spool or piston is movable between two limiting positions under the action of a spring and/or pressure forces acting on the spool. In each of these positions the spool opens or closes a particular pathway for fluid under pressure. For closing such a pathway for the fluid a sealing surface of the spool is brought in intimate sealing contact with a corresponding sealing surface, i.e. the valve seat of a fluid conduit or other component of the hydraulic system, e.g. a casing. It is clear that the corresponding sealing surfaces have to be matched carefully and have to be aligned with high precision in order for the pressure relief valve to function properly. Any misalignment or mismatch of the sealing surfaces may lead to pressure losses, leakages and/or other malfunctions of the pressure relief valve or the circuit to which the pressure relief valve is assigned to.
The above prior art solutions have the draw-back that the valve spout and the valve seat, on which the valve spout seals, have to be aligned very precisely in order to prevent malfunctions. In particular, misalignment of the valve spool, for instance due to production tolerances of the mounting position of the valve housing, would lead to leakages at the valve seat if the sealing members cannot be positioned properly to each other. This requires very narrow tolerances in the production of the valve components, in particular the position, parallelism and the concentricity tolerances of the sealing surfaces on the valve spool and the valve seat to each other. Furthermore, this requires very precise production tolerances of the mounting position and the alignment of the valve housing on an installation cavity, e.g. a housing of a hydraulic or pneumatic unit. Naturally, this leads to relatively high costs in the manufacturing process, not only for the valve itself, but also for the hydraulic or pneumatic unit for which such a valve is used.